First-year pay increases for unionized workers dropped dramatically in the first quarter of 1982 as more companies sought and received concessions from their employes in an attempt to stay afloat in a recessionary economy.

The Labor Department reported yesterday that contract settlements during the first three months of this year produced first-year increases averaging 2.2 percent compared with average first-year raises of 7.8 percent in contracts signed in 1979.

Increases over the life of the contracts negotiated this year--most of which are for 32 months--averaged 2 percent compared with 5 1/2 percent in the agreements negotiated three years ago, according to the report by the Bureau of Labor Statistics.

The BLS said the first-quarter bargaining was dominated by the concession settlements between the United Auto Workers union and Ford Motor Co., and the Teamsters union and Trucking Management Inc., the bargaining arm for the nation's unionized trucking industry. Agreements in those two contract talks affected 70 percent of the 645,000 workers in the 65 major bargaining units (at least 1,000 covered workers) affected by pacts signed in the first three months of this year.

The UAW and General Motors Corp. reached a tentative agreement in March. That pact gave the company an estimated $2.5 billion in concessions in return for increased job security. But the UAW/GM agreement was ratified and signed in April, placing it outside of the scope of the BLS survey.

According to another study, produced by the Washington-based Bureau of National Affairs, the decline in monetary contract gains was accompanied by a sharp increase in layoffs and plant shutdowns.

Nearly 77,000 workers were laid off for an average period of 3 1/2 weeks last February compared with nearly 39,000 workers laid off for a similar period in February 1981, according to the independent research and information company.

A total of 346,375 workers lost their jobs in the first three months of 1982. Of that number, 214,315 were placed on temporary layoff and 84,805 were laid off indefinitely, the BNA said.